Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for determining the location of an edge feature in an inspection image of a workpiece acquired by a machine vision inspection system, the method comprising using a computer to perform the following steps comprising: a) identifying an edge feature included in the image; b) defining a scan line orientation to be used for determining the location of at least one edge point of the edge feature; c) determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation; and d) determining the location of the edge point along the straight line based on the plurality of estimated image intensity values and their corresponding positions along the straight line.
2. The method of claim 1 , wherein determining the plurality of estimated image intensity values comprises estimating the image intensity values using bilinear interpolation.
3. The method of claim 2 , wherein for each of the positions along the straight line, the bilinear interpolation is performed utilizing the image intensity values of the four nearest neighbor pixels to the position.
4. The method of claim 1 , wherein at least one of the positions along the straight line is determined such that it nominally coincides with either a pixel row or a pixel column.
5. The method of claim 4 , wherein when one of the positions along the straight line is determined such that it nominally coincides with a pixel row, then estimating the image intensity value corresponding to that position comprises linear interpolation between the image intensity values of the two nearest neighbor pixels in the same pixel row.
6. The method of claim 4 , wherein when one of the positions along the straight line is determined such that it nominally coincides with a pixel column, then estimating the image intensity value corresponding to that position comprises linear interpolation between the image intensity values of the two nearest neighbor pixels in the same pixel column.
7. The method of claim 1 , wherein steps a) and b) are performed by configuring a video tool displayed on a display of the image, and steps c) and d) are performed by an edge point locating routine of the video tool, the routine comprising: instructions that control the machine vision inspection system to perform operations for determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation and that estimate the image intensity values by interpolating between the image intensity values of image pixels that are nearest neighbors for each of the positions along the straight scan line; and instructions that control the machine vision inspection system to perform operations for determining the location of the edge point along the straight line based on the plurality of estimated image intensity values and their corresponding positions along the straight line.
8. The method of claim 7 , wherein identifying an edge feature included in the image comprises positioning an edge-identifying element of a graphical user interface of the video tool on a display of the image.
9. The method of claim 8 , wherein the video tool is one of a point tool and a box tool, and defining a scan line orientation to be used for determining the location of at least one edge point of the edge feature comprises orienting a scan line orientation indicating element of a graphical user interface of the video tool on a display of the image.
10. The method of claim 8 , wherein: the video tool is a circle tool; the edge point locating routine comprises scan line determining instructions that control the machine vision inspection system to perform operations that define the respective orientations of each of a plurality of radially oriented straight scan lines that are distributed at a plurality of angles around the region of interest; defining a scan line orientation to be used for determining the location of at least one edge point of the edge feature comprises executing the scan line determining instructions; and the operations for determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation comprise operations that determine a plurality of estimated image intensity values corresponding to positions along each of the plurality of radially oriented straight scan lines.
11. A video tool for determining the location of an edge feature in an inspection image of a workpiece acquired by a machine vision inspection system, the video tool comprising: graphical user interface means positionable on a display of the image for identifying an edge feature included in the image; means for defining a scan line orientation to be used for determining the location of at least one edge point of the edge feature; and means for locating an edge point comprising: means for controlling the machine vision inspection system to perform operations for determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation; and means for controlling the machine vision inspection system to perform operations for determining the location of the edge point along the straight line based on the plurality of estimated image intensity values and their corresponding positions along the straight line.
12. The video tool of claim 11 , wherein the operations for determining the plurality of estimated image intensity values corresponding to positions along a straight line comprise operations that estimate the image intensity values using bilinear interpolation.
13. The video tool of claim 11 , wherein the operations for determining the plurality of estimated image intensity values corresponding to positions along a straight line comprise: operations that determine at least one of the positions along the straight line such that it nominally coincides with a pixel row; and value estimating operations such that when one of the positions along the straight line coincides with a pixel row, the value estimating operations estimate the image intensity value corresponding to that position using linear interpolation between the image intensity values of the two nearest neighbor pixels in the same pixel row.
14. The video tool of claim 11 , wherein the operations for determining the plurality of estimated image intensity values corresponding to positions along a straight line comprise: operations that determine at least one of the positions along the straight line such that it nominally coincides with a pixel column; and value estimating operations such that when one of the positions along the straight line coincides with a pixel column, the value estimating operations estimate the image intensity value corresponding to that position using linear interpolation between the image intensity values of the two nearest neighbor pixels in the same pixel column.
15. The video tool of claim 11 , wherein: the video tool is a point tool; the graphical user interface means comprises at least one of a point tool body and an edge selector; the means for defining the scan line orientation comprises the point tool body as oriented on the display of the image; and the operations for determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation comprise operations that determine the straight line such that it is collinear with the point tool body and that estimate the image intensity values by interpolating between the image intensity values of image pixels that are nearest neighbors for each of the positions along the straight line.
16. The video tool of claim 11 , wherein: the video tool is a box tool; the graphical user interface means comprises at least one of a region of interest indicator and an edge selector; the means for defining the scan line orientation comprises at least one of the region of interest indicator as oriented on the display of the image, a box tool orientation indicator as oriented on the display of the image, and a scan line indicator on the display of the image; and the operations for determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation comprise: operations that determine a plurality of straight scan lines that are aligned parallel to the defined scan line orientation and distributed within the region of interest; and operations that determine a plurality of estimated image intensity values corresponding to positions along each of the plurality of straight scan lines and that estimate the image intensity values by interpolating between the image intensity values of image pixels that are nearest neighbors for each of the positions along each straight scan line.
17. The video tool of claim 11 , wherein: the video tool is a circle tool; the graphical user interface means comprises at least one of a region of interest indicator and an edge selector; the means for defining the scan line orientation comprises means included in the means for locating an edge point, for controlling the machine vision inspection system to perform operations that define the respective orientations of each of a plurality of radially oriented straight scan lines that are distributed at a plurality of angles around the region of interest; and the operations for determining a plurality of estimated image intensity values corresponding to positions along a straight line that is aligned with the defined scan line orientation comprise operations that determine a plurality of estimated image intensity values corresponding to positions along each of the plurality of radially oriented straight scan lines and that estimate the image intensity values by interpolating between the image intensity values of image pixels that are nearest neighbors for each of the positions along each straight scan line.
Unknown
July 28, 2009
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